SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d6bc50dfa95974aec4154b170c76d924f3c3df78e18ba85a82fc2806ad2b54d' 
  AND token = 'mLATNkKIDbaX8z1HQ1i7CMu6Uf+gutHG3Rh0qivByvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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