SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf5a61937bc7591c19e768eee8a524484ec0b41db255f2a9b086d469bd481b2a' 
  AND token = 'FPQJU/rGLCGxQNIGuRnrdIDV42Qg6dQG/nhk6PbxWSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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