SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb76177ff6ddca3666a1dc108457f72e18bd4bbe3e5f72ac19b542367cff2d02' 
  AND token = 'iNRAv1VoZg39aeFMYgXnxem3UM20bWW3AT97o3mm+/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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