SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9d1552190cbd84b9486be37e5bdd2bafbd39262f1dff23d87de13a0c089d992' 
  AND token = '1+eJ+6dI/15/zOvKWZhfmG/EyOcaDs2K65qsF/WmGDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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