SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71fc7108fb32911b2217fbf664753265b1ccc1d48cd1d0c3e25b067563949de8' 
  AND token = 'bbKeyLNJ0N3OGPZx20HSR2BuFGkIbEC3lbCKEZyKk8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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