SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '435420a17a35ab8eb4d13bc799cd06a6bc11b1411297c9d0596a38fc7fe43d77' 
  AND token = 'oh9bLrKqoO+7kPBN0XD+HImmjSt7iLsJktXceF8MGrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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