SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b51803733cb3d5eb2b1f80475ddee52e6a96cf63193dce87c318a4140bb8b16b' 
  AND token = 'NbN6pk76mfRkz949uwskHeMTcI2rRfWkkCEmDXLdkLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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