SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ae558992bac163dfac5ea32980be84843f5756b449d96b4270192fc685b3175' 
  AND token = 'OP+Lf1fjeCDSR3BegTRc4n5ZJYz73MUGsrgD2E8fcUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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