SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f03ad824f8c580f101bdcbb065a645b1794279dc7b299ce75a7c14af9db2e463' 
  AND token = 'RGDbbwRlrZBez1foxON1mY6w3EFFf6CJFUzhymkAVx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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