SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc76d38c8a3acfa1674581ed82e09c05220b0ca14b6a4e04598316bf93fc68f9' 
  AND token = '53rbguzO//qh0oy1W0bwSGzGd6V1cEWxBUbFIC/X+Eo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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