SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '437ebd96148268bcd00bc6bd9ee02b0b45fe76d5229360bb3d84d340d3de73d6' 
  AND token = 'cmrQUtN9X+Bd/M3IMVbDocjbDhmLKYgm4QjcaYZ+hpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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