SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14c88bc09b60b60aba97fdf220dda8d6be2792ee26743234b727df0b0b055331' 
  AND token = 'IgAt7AqOcfiDcFFjS8pgCDe9/S0iI1hoU1cqVp6jdUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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