SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a0ed8e5451ad32f6e4ea70a953885fe75f15d90c5cdeb9ca41710733c05f861' 
  AND token = 'qYgnR2YCwJpWtWnk9PgFN8ZfVAwnodgeuqTlo1Ct2wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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