SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '851e20b09449aacf1e647813f8ebeb97116bd339c906c04fd917bea8c45946b2' 
  AND token = 'B7z8CSi6QE3wuW46sl9UIKO7rbMIzKLf1pdQ19FAYxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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