SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4bc3a66c9db9d18fd043df48b2d29562d0fe7971cb594405f2d8edc414cb6b9' 
  AND token = 'ZTMbpGb0lkpuaNKiDwpj6CL2k8kT71HJty8iGGmOSW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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