SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f08e8ea10d76afd624d91506b0fc07fc557029cd6a358083529e0fed809aaae' 
  AND token = 'CumV+PEvbFh3Ik/zg6CNQtVGZXYq7jE98CKz3swoy3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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