SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb24016ae901d87460995345929eed1554f59f3284037048bb7459adebcc8c3b' 
  AND token = 'Z5n9C8Am3Tl86z3kT5J9PKbxmCHyu72W9nbRZIa+om0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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