SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '84156278a07ef1d76595413384fc1d90afff6c9c7d807d8e2d8dd276f6b39064' 
  AND token = 'u4Ccpf2jWpXG3Vv++yR6TmcKdLYpJPS8+HqwXt1CQtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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