SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a9135c06f0dd7492aacc1668a78d52c85b2a6949e3dbabca8895097435c3a51' 
  AND token = 'aEw+L/euV+53shc/kBYBNBjsoHn1mLpVsM5QPXYnz+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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