SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64e64737286727a956e7402b090910a5a955128348eb51544c28f1969718710c' 
  AND token = 'jLPh1w2R9NHFKt2S/Qu3aXhWdsJAyokGdlfPA4wi77A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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