SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fca9aace54d33104d1f260b2e8e4f93097119279476d4fde397990786c757233' 
  AND token = 'F8B+Coci19Fs+hwaW9y9yiMrPhv+Yr4RhgGZ0jY4KZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}