SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed61689775a307510681a230e8249f1f4442b14f343863384fd16f5c3defa925' 
  AND token = 'K8hbeTwi5KLszJjCpYDM9MunblaOKQ1+FalklPCvguM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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