SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7002c104ee774dc637dd11ec4327885388ea0069103a80585067a4c0cffe306d' 
  AND token = '7M+qFuVgCW7ZmMuumak33veuYZRJWKy73pkAecAOcpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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