SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b08c5d4845592d0bb0174d7f4454d91c6ced89d6efdba921cfaf572432b3983' 
  AND token = 'jNCGxqWDRXMKJPbp+EmBpTJ4QlCYZ1mZF7ujwNaS4MU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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