SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09be0101f265344365e297032415c7c32e92b01d5ff5478ffeb3a694ef835b82' 
  AND token = 'FRUFlvAv3vlP3d43UqEcNmMW1RRUiFeyp3zjAHBMU3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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