SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb6fb5cfcb2c9fdcbb3c89c3e63079a682e318181f624ceb14b20624bc0026ed' 
  AND token = 'vo5L+1fHX62Jlb5gMQW8ChHtTittMYXNVEuCBKqdjjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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