SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7b4edaed62edc687adb7c8572d8c4232bd472fb3f474885ef2f309305c86f6e' 
  AND token = 'pM9WO0LD3k0QkZfzwEPIb+WKWjgMrFaMksjFEcrIYUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}