SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2adb25dca8eeb2a448acc1e9410db998f0048ef53aa0576f0b41739b366ed5e7' 
  AND token = '5bkgnVovo+X55Wz0VvNujaS2zhynuXm2JOSUW/BxY+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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