SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87cd4cb558a2d865bf4c034f2817892c71834b8e062d147dc8f039974b3747d4' 
  AND token = 'KUaqlJeZi1JILtX4DpZMpyzcBYrEpM3RzOV19JQvtr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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