SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eebe473e265b979c577baf08cd6e77df38ac3155103eb9d8e16df08862099c76' 
  AND token = 's17lpHhuGtfdtSptjUGqb8ZEUeW55CoRyClBb+EVnwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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