SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cbe7dc6b4f0881eb82f27b0cfa2bc553875aeb4bb4476e75482646966190c1b' 
  AND token = 'M0d3DK4e8YQvD6byRt1IBiQ2kguq0so5/oNFdBZzVw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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