SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2f4082810d2762cb95035176f7bdfcf5bb26b6dcd2bb28fadf3433606f0375f' 
  AND token = 'JLg43EpGqInhlfpI+7vsJ2ymnZKqyYGc35YjewUlnsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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