SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '75a56d040b132158ccc082abec1a1ba0790304296e676975aa97c49bccd2d350' 
  AND token = 'AIKcbJFgxiLh5y7pGBbaqf/QIDJYR4SWcX/v4NMaDmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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