SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '820a3a92123d669941714a28815c5712eaff634eba69c8b497e25cc366d913ff' 
  AND token = 'GLloPvtB8aTm4CH9qr4m7k27iK+H1hUCbhsg4uPYIsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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