SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83812159aa2d05e94df515e09b3a6e915157d32db30ac52a0ec6b91b7cb3ab77' 
  AND token = '84zCDd4wD5eBsrUZPurF5R9Rou2boRriX0Nxfi2Eu0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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