SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15ddc64e9489ac2369e6d3f316d97aed57aca44867f1925e1c027b4d492ebe5' 
  AND token = '7/IcBr0NunItrq/4vdfMw4wLZwazvHwIuPWgSZg8As4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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