SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40b89a1f6c3dad2f2f6115e3f2d5625fad2fed46ca7bd222cb760c9e58cdfc99' 
  AND token = 'jUEdeUZEKy/sdSRL9y8dg+iuPBInPi0rdbWZfiiuYUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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