SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e008aa29fe933e08019811e43b11f570fd8d1f68eb913a4d94c26a6c065bce' 
  AND token = 'VbzMJnc3TM9UtzvSAKoACaPKzBgRczyDSyleYmx7h+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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