SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a03335755bf62311623a4bbfa14139b204a5354fbc8746d1623a03e9d3a60f8' 
  AND token = 'aUi+O3mpsJFsxpaYUntehR2wpj6KYlOzXvfrlECyKG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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