SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '474ab201b97672bff6747c5428c74962f8015c492e9d22a5fc20f04e1f8c6c87' 
  AND token = 'JLpT/4xGEAmze4PLi0sBdjoVIaJK46fz79Avu7B+r4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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