SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6622bedccbe72442a40b058bcc575f350aabcdfafe62058942ef5c90dbfb229' 
  AND token = 'gm8tSPxzLMtimhE213t8Ae0S7vfRdI4/VsoCayQsJ70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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