SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f6ac3b82fd19afbd5f71c9884319caa03da6eae859f332691d4c2fc99eb2825' 
  AND token = 'BYRf4qfU1SRBmTobb/iw6kXkXajljCeCRG61ZjmfOSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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