SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c07839291b7ca4d10800204fd695c0f14e1e62ff64583bd21abe7299ddfafc3' 
  AND token = 'z0P65jpxi0dZcZlZN6IJpAm/YPQ2wXLMhYDmIe5Gczw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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