SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a707e0ea25422da9647242ecc2640422cbda7d4807c6e293d6a782c2d495897f' 
  AND token = 'meIX1b0wUEWCEStPvdiH1RzIBZs5EEm11gfr3/5w/5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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