SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a84f2ade8eb61c60d698355fbb1302dd7e622ec42f8294ad8ba7cc52d8a135c7' 
  AND token = 'z/CjDHGDUv9kI5oDJUN9Lv203JNC6Zl+BZVcfLx6Akg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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