SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42925ebc815392bdf03c56b9d59fd2ad747fbe993931cdbf9a13935610e32a27' 
  AND token = 'GqT9Sw6VV0vbVq7ix4okTZRd3TnqgJxgp2A/GNAG48A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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