SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6381dfc227097bbc37a1c78c22e0411aa8b45a424790516b1b5beecbf84037b' 
  AND token = 'T2T8ZWw3ALu/lUy6yMflvqwsprLn8qbSPdFXwmgoXm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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