SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2ab74d5e5486e1f19b05536b8a05dd197d2ef1f625bf11b06a0304ab4e270e4' 
  AND token = 'O0LHhsT9Gn7zZ/Sy5X0PvOVRDD2m+RdjB36Hg8ywFxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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