SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75fa12eaf1019c57762ff957cf0312077fba327f18b50a49e0804efb309e4c2e' 
  AND token = 'txo/gKnzZVq+pZ+qJY5IEUf79ph6KOHF0Po8diPa8RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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