SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b49075042040fde8da1947e4982cb523aed1e86120563f762210f89266ef159' 
  AND token = 'F5dqCvNQYwuvPsa4rg+11r/TgeulLBkCwubBuszglII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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