SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf2faf022a44008e91aa734e7ffab06f56ce7fb33a0feaa163c38604b8120344' 
  AND token = 'GxR2TI+YB9fyUaSThz8JIV/uniBccvd3IqCwyqfQFwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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