SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '298b7918bc225868dbc79ea90aa0216cf64707871543097b0b111f1477a9d50b' 
  AND token = '4BjUsTP8cXl1DVHMAv0gsrgOyitjuPf4jXWzmmN4DTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}