SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39ae3adfdaa6736d6e27cc49145cb1a0faee1f308e2138fc77bb88067e7fb8d0' 
  AND token = 'W4uSYzR3GoqPeew4x2GUubs5nPGNabADjoUyvCfYS5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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