SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77efddce2a799d3737bc17717d985fecd60357ab7ed966c13d831e079a1d1e2c' 
  AND token = 'hc3VBjmYIzfOGrMiUnnXNMU+6jmhtRUBZO+OutLL3ZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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