SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9685725de43dbb0e007f77bc479c7d77e5e7904d4b78ea667876c5e69cc47fb' 
  AND token = 'LWqMhBLMtkVfm3jymfgBXMBXFmf06yGLCAeIY77ARxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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