SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bafba644efe686730b67f196a71fed5d0fab7bc82e734cca0067df7071553b2' 
  AND token = 'RCkiiFSCph9o03WrvRUe2yIOnwUkwAgoh4Cw4/2eqg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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