SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c646d6c20959bc4b472d32e08215b7a86e25b8339b4cde237f1710e2d58bfea' 
  AND token = 'dcznw1rB+i5daKNkhazs+2c6RFbbgIFSuwIz5hzoGHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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