SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d20450bb75898d3239e76120daac7c1df255028562eb96c54bbff1a79f3bbb0' 
  AND token = 'crAShhDrmTlVeaIOzmfVPtlNxHU9X2Ksgu2Ayp/amGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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