SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b9c4c98382a00ce5aac45efecc560d2ef6c601acda98431ccc7450a01c1a421' 
  AND token = 'lhkqMYfHWMWRpISENK7NUTxnE6Q7Hzjws5Ktx4hHJkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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