SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cff456331035939a9274b665b7478c9fe6b531eb17c425cded13e7136cbd8d2' 
  AND token = 'qS7wUhOFa00WYruXK7GChVyCcNm8dnV0cPXj7evQKiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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