SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cebebec7f5ce93ce77d0dcc1b16bd82f022028ecee7c7fc18304360009bea04' 
  AND token = 'ukzl43wJ3bBNxNz8ENLJXIRI53WZAWvjaVEpQVNUnf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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