SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e100f3998cbaf42c356c531f5dda719154bf43dd0dedcab76f37e65db05893c6' 
  AND token = 'XKsQ6YffLVwyU6yZeVB9uqjOMK5HYDEiSo5S2LuJCsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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