SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c18570319b4d99290c5e8e88a49163dfdd48c076bb2edd37cd7bc304517510a9' 
  AND token = 'WmbYuu+sq4m7NnfVRwwRbFOY3hhpOtZMDqGK8VS2wHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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